Condenser



March 9, 1965 c c, PEAKE ETAL 3,172,465

CONDENSER Filed July 5, 1963 5 Sheets-Sheet l Fig.l.

WITNESSES INVENTORS MM Charles C. Peuke Marion George Flesher Mamh 1965 c. c. PEAKE ETAL 3,

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United States Patent 3,172,465 CONDENESER Charles C. Peake, Media, Pa, and Marion George Flesher, Chicago, Ill., assignors to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed July 5, 1963, Sen No. 292,868 9 Claims. (Cl. 165-97) This invention relates to surface condensers, more particularly to a vapor condenser provided with means for venting incondensible gases, such as air, and has for an object to provide improved apparatus of this type.

In order to reduce the time to which the liquid conducting tubes are subjected to erosion at the inlet ends, where it is most severe, it is beneficial to operate a condenser with circulating liquid flow in one direction half of the time and in the other direction the other half of the time. Also, since condensers of this type usually employ lake, river, or sea water, it is desirable to reverse the direction of circulating water flow to promote condenser tube cleanliness by minimizing organic growth on the water sideof the tubes,

This method of operation, however, does not permit a condenser with the conventional shell side design to be properly vented of non-condensible gases when the flow of circulating water is in the reverse direction. Incondensible gases must always be vented from the cold end of a condenser. For this type of operation, the cold end changes with reversal of water flow. Placing a vent line ateach end of the condenser with appropriate valving between the condenser and air removal equipment has been proposed. However, this arrangement is inadequate, since the internal arrangement of the vent path must also be considered in order to maintain optimum ethciency of heat exchange and to prevent unbalancing the vapor and incondensible gas flow paths. n

In order to assure the best possible performance, according to this invention, the condenser should be vented in such a manner that incondensible gases are removed from each portion of the condenser at a rate proportional to the rate at which vapor enters that portion. This then requires that the cold end, where the heat exchange potential is greater due to a greater temperature difference; be vented at a higher rate than the hot end. Also,.since, for facility of design and manufacture, the cross-section of the condenser normal to the axes of the liquid conducting tubes is the same at all planes normal to the length, the pressure drop of the vapor flowing from the vapor inlet to the incondensible gas or air olftake space is greater at the cold end than at the hot end. In view of the above, it is highly desirable to maintain the air oiftake space of the cold end at the lowest absolute pressure and also to vent the incondensible gases at the greatest rate from this end.

Accordingly, another object of the invention is to provide an improved arrangement for venting incondensible gases from a surface condenser in which the direction of flow of cooling liquid may be reversed during operation.

A further object is to provide an arrangement for venting incondensible gases from a vapor condenser of the tube and shell type, in which the direction of flow of cooling liquid through the tubes may be reversed, when desired, without unbalancing the heat exchange function and without adversely aifectin'g the collecting and venting efficiency of the condenser.

Briefly, in accordance with the invention there is, provided a surface condenser of the tube and shell type having a nest of tubes arranged to provide, for example, a single pass of cooling liquid for condensing the vapor. The tubes are arranged to provide an open core, substantially devoid of tubes, extending lengthwise of the tubes and disposed in such a manner that substantially all of the tubes are traversed by vapor en route to the core. Hence most of the vapor is condensed before reaching the core, so that only aerated vapor or incondensible gases collect in the core.

When cooling liquid is directed in one direction through the tubes, there is established a fcold end in the vapor cooling space adjacent the inlet of the tubes and a hot end adjacent the outlet of the tubes, with a progressively rising temperature gradient in the one direction. I

When cooling liquid flow through the tubes is reversed, the cold and hot ends are also reversed.

To accommodate proper venting of incondensible gases, regardless of direction of cooling liquid flow, venting duct structure is disposed in the open core. This venting structure includes a pair of ducts disposed in side-by-side relation with each other and extending from one end of the tubes to the other. Each duct is provided with a plurality of orifices of graduated size, decreasing in size in the one direction in one duct and decreasing in size in the opposite direction in the other duct, In other words, the orifices decrease in size from the cold end to the hot end to accommodate the, decreasing rate of condensation and attendant decreasing rate of collection of the incondensible gases in the open core.

When the condenser is operated with cooling liquid flow in the one direction, the one duct is rendered operative by connecting to a vacuum producing device such as an ejector, while when the condenser is operated with cooling liquid flow in the oppositedirection the other duct is rendered operative by connecting to the ejector.

The above and the objects are effected by the invention as will be apparent from the following description and claims, takenin connection with the accompanying drawings, forming a part of this application, in which:

FIGURE 1 is a cross-sectional View of a surface condenser incorporating the invention;

FIG. 2 is a longitudinal sectional view taken on line IIII of FIG. 1;

FIG. 3 is a sectional view taken on line III-4H of FIG. 1, with portions of some of the tubes cut away for clarity; and

FIG. 4 is an enlarged fragmentary view taken on line IV-IV of FIG. 2.

Referring now to the drawings in detail, in FIGS. 1 and 2 there is shown, at 10, a surface condenser of the radial-flow type comprising a tubular shell 11 having an inlet 12 for admitting exhaust vapor, for example, steam, at the top and a condensate outlet 13 at the bottom to which the condensate may flow from a hot well structure 14 disposed 'thereabove. The ends of the shell are closed by a pair of tube plates 16 and 17 which serve as supports for the terminal portions of a plurality of tubes 18 defining a tube nest 19 extending longitudinally of the shell.

Water box structures 20 and 21 cooperate with the tube plates 16 and 17, respectively, and serve to conduct cooling water through the tubes in either direction, that is, from right to left as' indicated by the solid line arrows A in FIG. 2 or conversely, from left to right in the reverse direction. Accordingly, the water boxes 20 and 21 are provided with suitable water conduit connections 22 and 23, respectively.

In the arrangement shown, the condenser is of the single pass type, that is, water flows through the tubes 18 in a single direction.

The space 25 surrounding the tubes 18 is known as a tube field and is the flow passage defined by the tubes 3 18 for the exhaust steam flowing therepast in heat exchange relation therewith.

The spacing of the tubes in the tube nest 19, as best shown in FIG. 1, is such that the tubes of the outer annular group of tubes 26 are disposed in radially converging alignment with each other, thereby forming radial steam flow paths 27, an intermediate annular group of tubes 28 disposed in a diamond-shaped pattern thereby providing a more tortuous flow path for the exhaust steam, and a central open core 30 substantially devoid of tubes with the exception of two smaller innermost groups of tubes 31 and 32 disposed therewithin for subcooling the incondensible gases remaining in the flow of the exhaust steam. For simplicity, the term air. is hereafter employed for aerated vapor and incondensible gases.

Intermediate the ends of the tubes 18 are a plurality of intermmediate spacer plates 35, 36, 37, 38, 39, and 40 disposed in substantially parallel uniformly spaced planes intermediate the end portions of the tubes. i These plates .35 to 40, inclusive, lend further support to the tubes and are further employed to provide a plurality of bays 41, 42, 43, 44, 45, 46 and 47, respectively, or steam lanes to permit the exhaust steam to flow in separate radially inward flow paths from the steam inlet 12 to the central core 30, as indicated by the arrows B in FIG. 2.

As thus far described, the apparatus is substantially conventional and operates in the following manner. Circulating water from any suitable source (not shown) for example, sea water, river water or the like is directed through the conduit connection 23 into the water box 21 and then flows through the tube nest 19 from right to left and exits into the water box from whence it is directed downwardly and outwardly through the conduit connection 22. back to the source. concomitantly therewith, exhaust steam from steam utilizing apparatus of any suitable type, for example a steam turbine, is admitted through the steam inlet 12 into the shell 11 and flows circumferentially within the shell and radially inwardly through the tube field towards the open .core

and, in so doing, the steam follows the steam flow paths,

indicated by the arrows B in the bays 41 to 47, inclusive. As the steam flows past the tubes, the outermost group of tubes 26 serve to cool the vapor progressively, thereby initiating condensation of the vapor. The condensate drops over and around the tubes by gravitationaleffect to the hot well 14. The steam not condensed in the outer group of tubes 26 is subsequently condensed in the intermediate group of tubes 28 and, at the same time, incondensible gases such as air and the like are cooled to a lower degree before collecting in the core 30. This air conventionally is withdrawn. from the core by suitable air otftake means.

This invention is concerned with an arrangement for collecting and removing the air from the open core 30, which arrangement will subsequently be described in complete detail. Considering now the operating characteristics of the surface condenser 10, as the circulating water flows through the tube nest 19 from right to left, as indicated by the arrows A, the water progressively becomes heated so that by the time it arrives at the water box 20 it is at its highest temperature value. Accordingly, the bay 47 at this time is considered the cool end of the condenser, while the bay 41 is considered the hot en of the condenser. That is, as the steam flows through the bays the steam flow through the bay 47' undergoes a larger heat exchange effect, thereby promoting greater mass flow of steam therethrough with a larger degree of condensation than the subsequent bays 46 to 41 (the hot end) of the condenser. Since a higher heat exchange eifect occurs in the cold bay 47 than in the other bays 46 and 41 more steam is condensed in cold bay 47 and, since the rate at which the air collects in the open core 39 is proportional to the rate at which the steam condenses in that bay, more air.

' collects in bay 47 than the others.

Hence, at the cold end of the condenser, where the heat transfer effect is greater due to a greater temperature differential between the water flowing in the tubes and the exhaust steam flowing therepast, more mass flow'of steam is obtained. Accordingly, the air must be vented at a higher rate than the air collecting in the open. core from the hot end of the condenser.

In the condenser arrangement shown, the cross-section (see FIG. 1) normal to the axes of the tubes is substantially the same at all points along the length of the tubes, that .is, the cross-sectional aspect of the tube nest 19 and the field 25 is uniform, hence the pressure drop of the steam flowing through. the bays is greater at the cold end than at the hot end because of the greater temperature diiferential at the cold end.

Since during operation, the surface condenser 10 is operated part of the time with circulating water flowing in the direction reverse to the arrows A, to minimize erosion and inhibit the formation of marine life and the collection of foreign matter. in the tubes which would otherwise reduce the flow of circulating water therethrough, the hot and the cold ends'of the condenser are also reversed. Accordingly, during such reversed operationof the condenser, the rate of collection of air in the core 30 also reverses.

In accordance with the invention, there is provided dual structure generally designated 59 disposed within the open core 31 for collecting the air at the optimum rate, regardless of the direction of circulating water flow through the tubes 18 inthe manner mentioned above.

This structure 50as illustrated in the drawings, comprise a right half 51 and a left half 52 substantially identical in structure but reversed with respect to each other, as will subsequently be described in more detail. Accordingly, the right half portion 51 will now be described in detail.

The structure 51includes an upper plate or wall member 54 extending transversely from the center line of the condenser to a region adjacent the innermost row of tubes in the tube group 28 and preferably inclined somewhat with thehorizontal to minimize collectionof condensate thereupon. This wall 54 extends in a direction parallel to the longitudinal axis of the condenser from the left-hand tube plate 16 to the right-hand tube plate 17. A lower plate or wall member 55, substantially identical to the plate 54 and disposed therebetween in spaced parallel relation therewith, extends substantially to the same degree transversely and longitudinally of the condenser. A vertical wall or partition member 56 isdisposed on the vertical center line of the structure with its upper and lower marginal portionsin continuous sealing contact relation with the upper wall 54 andthe lower wall 55, respectively, and extends longitudinally of the condenser from the spacer plate 35 to the spacer plate 40.'

Between the upper and the lower walls 54 and 55 there is provided an intermediate wall member 58 formed with an angular cross-sectional shape (see FIG. 4) and having one end portion disposed in continuous abutting relation with the vertical partition member 56 and its other portion disposed in continuous abutment with the upper wall 54. The. wall member 58 is of. lesser length than the upper wall 54 and of substantially the same length as the partition member 56, i.e., it extends from the spacer plate 35 to the spacer plate 40.

All of the spacer plates 35 to 40 inclusive are provided with openings 60 in their central portions, which openings substantially conform to the area that is included by the upper and intermediate walls 54 and 58 and the partition 56, so that these members jointly form a longitudinal duct or passageway 61 that extends from the spacer plate 35 to the spacer plate 40. An end wall member 63 is provided to close the duct 61 at its left end (see FIGS. 2 and 3) in the region adjacent the spacer plate 35 and restricted flow communication is provided between the left end bay V 41 and the duct 61 by a small orifice 64 formed in the end wall 63. The opposite end of the duct 61 is in unrestricted open communication with the right end bay 47. However, a deflector plate or bafile 65 is provided in the bay 47 extending downwardly into spaced relation with the lower plate 55.

Referring to FIGS. 1 and 4, it will be seen that the innermost tube group 31, employed to subcool the air is disposed in the space formed by the wall members 55 and 58. Accordingly, the air collected in the open core 30 is directed past the tubes 31, as indicated by the arrows C.

The intermediate wall 58, as best shown in FIGS. 2 and 3, is provided with a series of orifices 68, 69, 70, 71 and 72 progressively increasing in size from left to right and each communicating with its associated bay, 42 to 46, inclusive. Hence, the air after flowing through the tube group 31 is directed into the longitudinal duct 61 through the orifices 68 to 72 at the rate controlled by the area of these orifices. duct 61 flows from left to right, as indicated in FIG. 2, and, upon leaving the duct 61, is deflected by the bafile member 65 in the cold end of the condenser (bay 47). The air is then directed from the condenser by a suitable air ofltake conduit 74 which extends through the righthand tube plate 17 and through the water box 21 to a region external of the condenser. This conduit 74 is connected to a suitable reduced pressure inducing device (not shown), for example a steam actuated air ejector, as well known in the art, by means of the conduits '75 and 76 illustrated diagrammatically in FIG. 2. A suitable valve 77 is employed in the conduit 75 to control the flow of air through the air offtake 74 and the conduits 75 and 76 to the vacuum inducing apparatus.

In operation, with the circulatingwater flowing from right to left through the tube nest as indicated by the arrows A, since the bay 47 is disposed at the cold end of the condenser, the bay 46 is the next to coldest bay, etc., proceeding to the hot end of the condenser (bay 41), the pressure drop across the bays attained by the progressively decreasing heat transfer relationship of the tubes in the bays is such that the largest pressure drop is induced in the bay 47 and the pressure drop successively decreases from the cold bay 47 to the hot bay 41. Accordingly, the air collected in the open core 30 from the bay 47 is directed to the air oiitake tube 74 with minimum restriction to flow. The remaining bays 46 to 41, direct the air through their associated orifices'72 to 68, inclusive at a progressively decreasing rate in accordance with the decreasing pressure drop, so that venting of the collecting air in the open core 30 is controlled by the structure 51 including the orifices 68-72 and 64" in a highly efficient manner to provide a balanced heat exchange relationship in the condenser and venting of the minimum amount of condensible vapors.

It will be seen that as the air flows through the orifices 68 to 72, the air streams merge with each other in the duct 61 and are directed from the duct through its open right end and thence around the baflle 65 to the air offtake conduit 74. As the air flows around the bafile 65, it again contacts cold tubes and is cooled and more of the condensible gases present are condensed.v This condensate then drops around and past the tubes and subsequently rejoins the falling condensate on the Way to the hot well 14 for collection. As the condensate there collects in the hot well 14, it is withdrawn through the condensate outlet 13, as well known in the art.

When the condenser is employed with circulating water flowing through the tube nest 19 in the reverse direction, the thermodynamic operational characteristics of the condenser are concomitantly reversed. Accordingly, to maintain the optimum heat exchange relation without unbalancing the heat exchanging function of the condenser 10, there is provided the second or left-handed duct structure 52 as mentioned earlier in this specification. It will be seen that the left-hand duct structure 52 is substan- The air thus collected in the 6 tially the reverse of the duct structure 51. Stated a1iother way, the duct structure 52 may be duplicated by rotating the duct structure 51, in a horizontal plane, about an angle of 180.

More specifically, the duct corresponding to the duct 61 is open at the left-hand end, as illustrated at 81 in FIG. 3, and blocked at the right-hand end wall member 82 similar to the plate 63, with restricted flow communication between the duct 80 and the bay 47 being obtained by a restricted orifice 83 of substantially the same cross-sectional area as the orifice 64. Also, the intermediatewall member 84 is provided with a series of orifices 85, 86, 8'7, 38 and 89 disposed in individual communication with their associated bays 42 to 46, inclusive. However, since the bay 41 is now at the cold end of the condenser, while the bay 47 is now at the hot end of the condenser, the orifices 85 to 89 are substantially identical in cross-sectional area, but in the reversed sequence, to the orifices 68 to 72 described in conjunction with the right-hand duct structure 51. There is further provided a second baflle member 90 disposed in the bay 41 of substantially the same size and shape as the bafile 65 disposed in the bay 47.

' Accordingly, when the condenser is operated with reversed water flow, the rate of collection of air in the duct structure is reversed. The air is directed from right to left by the duct structure 52 and is removed from the condenser by an air ofitake conduit 91 extending through the water box 20 and the tube plate 16 into communication with the bay 41. The air oiftake conduit structure 91 is connected to the same vacuum inducing source (not shown) by conduit structure 92 disposed in parallel with the conduit structure 75 and communicating with the conduct 76. There is also interposed in the conduit 92 a valve 93 which valve may be substantially identical to the valve '77. During operation with reversed water fiow, the valve 93: is moved to the open position, thereby to permit the flow of the air from the duct structure 52 to theleft, while the valve member 77 is moved to the closed position, thereby to prevent flow of venting air through the .air ofitake 74. Conversely, when the condenser is operated with circulating water as described in conjunction with the first duct structure 51, the valve 77 is in the open position while the valve 93 is in the closed position.

By referring to the figures, especially FIGS. 3 and 4, it will be noted that the central partition 56 is common to both duct structures and has its lower poriton extending from the intermediate to the lower walls 58 and 55, respectively. Hence, the venting air flows to each of the ducts 61 and 80 are substantially isolated from each other by the partition 56, so that operation of the condenser with water flow in either direction is assured at the optimum value with substantially little or no short circuitmg of flows from one duct to the other during operation.

It will now be seen that there is provided an exhaust vapor condenser that is provided with a dual venting arrangement that permits operation of the condenser with circulating Water flow in either direction without impairing the efliciency of heat exchange and venting of the condensible gases.

Although only one embodiment of the invention has been shown, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof.

We claim as our invention:

1. A surface condenser comprising a tubular shell having an exhaust vapor inlet and a condensate outlet,

a nest of tubes disposed in said shell and arranged to provide an open core,

a plurality of spaced parallel plates extending transversely across said tubes and dividing said shell into a plurality of bays communicating with said inlet,

whereby inconde'nsible' gases and vapor to be condensed 7 flow along said bays past said tubes and toward said core, and the incondensible gases collect in said core, first means for directing a cooling liquid in one direc tion through said tubes, said tubes thereby efiecting progressive cooling in said bays with a resulting duct structure for conducting the collecting incondensible gases from said core, said duct structure having a plurality of first orifices of graduated area for progressively venting the collecting incondensible gases from each bay at a rate increasing in said opposite direction when the cooling liquid is directed through said tubes in one direction,

a plurality of second orifices of graduated area for progressively venting the conducting incondensible gases from each bay at a rate increasing in said one direction when the cooling liquid is directed through said tubes in said opposite direction, and

means for restricting short circuiting flow of incondensible gases between said first and second orifices.

2. The structure recited in claim 1 in which said plates are provided with openings disposed in said 7 core and aligned with each other, and

said duct structure extends through said plate openings and provides a first gas flow passage directly communicating with said first orifices and a second gas flow passage directly communicating with said second orifices.

3. A surface condenser comprising a tubular shell having a pair of axially opposed open ends and having an exhaust vapor inlet at the top and a condensate outlet at the bottom,

tube plates closing the axially opposed ends of said shell, 7

a nest of tubes extending from one end to the othe end of said shell and having their terminal portions supported by said tube, plates,

said tubes being arranged to provide an open core extending in an axial direction in said shell with the tubes adjacent said core constituting a cooling section, for incondensible gases,

first water box structure associated with said tube plates and adapted to direct a cooling liquid in one direction through said tubes, said tubes thereby effecting cooling in said cooling section with a tube temperature gradient rising in said one direction,

second water box structure associated with said tube plates and adapted to direct said cooling liquid in the opposite direction through said tubes, whereby said tubes attain tube temperature gradients in said opposite direction in said cooling section,

dual duct structure dsposed in said core and providing first and second passages,

first orifice means for progressively conducting the collecting incondensible gases to said first passage at a rate increasing in said opposite direction when the cooling liquid is directed through said tubes in said one direction,

second orifice means for progressively conducting the collecting incondensible gases to said second passage at a rate increasing in said one direction when the cooling liquid is directed through said tubes in said opposite direction, 7

a partition disposed between said first and second orifice means for restricting short circuiting flow of incondensible gases between said first and second orifice means,

first conduit means for venting the incondensible gases from said first passage when the cooling liquid is directed through said tubes in saidone direction, and

second conduit means for venting the incondensible gases from said second passage when the cooling liquid is directed through said tubes in the opposite direction.

4. The structure recitedin claim 3 and further including a plurality of parallel spacer plates extending transversely across said tubes and providing a plurality of bays for directing the vapor from said inlet to said core in a plurality of separate paths, and

said first and second orifice means provide first and second communications between said bays and said first and second passages, respectively.

5. The structure recited in claim 3, in which said partition extends into said dual duct structure and partly defines said first and second passages, and

said duct structure extends longitudinally in the same direction as said tubes.

6. The structure recited in claim 3 and further including a plurality of parallel spacer, plates extending transversely across said tubes and providing a plurality of bays for directing the vapor from said inlet to said core in a plurality of separate paths,

said spacer plates being provided with central openings through which said dual duct structure extends, and

said first and second orifice means are graduated orifices formed in said duct, structure and providing first and second communications between said bays and said first and second passages, respectively.

7. A surface condenser comprising a tubular shell having a pair of axially opposed open ends and having an exhaust vapor inlet and a condensate outlet,

tube plates closing the axially opposed ends of said shell,

a nest of tubes extending from one end tothe other end of said shell and having their terminal portions supported by, said tube, plates,

said tubes being arranged to provide, an open core extending in an axial direction in said shell with the tubes adjacent said core constituting a cooling section for incondensible gases,

first water box structure associated with one of said tube plates and adapted to direct a cooling liquid in one direction through said tubes, said tubes thereby eftecting cooling in said cooling section with a vapor pressure drop gradient diminishing in said one direction,

second water box structure associated with'another of said tube plates and adapted to direct said cooling liquid in the opposite direction through said tubes, whereby said tubes attain tube temperature gradient in said opposite direction in said cooling section,

first orifice means for progressively venting the collecting incondensible gases at a rate increasing in said opposite direction when the cooling liquid is directed through said tubes in said one direction,

second orifice means for progressively venting the col lecting incondensible gases at a rate increasing in said one direction when the cooling liquid is directed through said tubes in said opposite direction, and

means for restricting short circuiting flow of incondensible gases between said first and second orifice means.

8. A surface condenser comprising a tubular shell having a pair of axially opposed open ends and having an exhaust vapor inlet and a con densate outlet,

tube plates closing the axially opposed ends of said shell,

a nest of'tubes extending from one end to the other end of said shell and having their terminal portions supported by said tube plates,

a plurality of spacer plates disposed in spaced parallel relation with each other and dividing said shell into a plurality of bays extending transversely to said tubes,

said tubes and said spacer plates being arranged to provide an open core extending in an axial direction in said shell with the tubes adjacent said core constituting a cooling section for incondensible gases,

first water box structure associated with one of said tube plates and adapted to direct a cooling liquid in one direction through said tubes, said tubes thereby effecting cooling in said cooling section with a tube temperature gradient rising and a vapor pressure drop gradient diminishing in said one direction,

second water box structure associated with another of said tube plates and adapted to direct said cooling liquid in the opposite direction through said tubes, whereby the tube temperature gradient and the vapor pressure drop gradient in said cooling section are reversed,

a duct structure disposed in said open core and extending towards said tube plates, said duct comprising first orifice means for progressively venting the collecting incondensiblegases from each bay at a rate increasing in said opposite direction when the cooling liquid is directed through said tubes in said one direction,

second orifice means for progressively venting the collecting incondensible gases at a rate increasing in said one direction when the cooling liquid is directed through said tubes in said opposite direction, and

means for restricting short circuiting flow of incondensible gases between said first and second orifice means.

9. A radial flow surface condenser comprising a tubular shell having a pair of axially opposed open ends and having an exhaust vapor inlet and a condensate outlet,

tube plates closing the axially opposed ends of said shell,

a nest of tubes extending from one end to the other end of said shell and having their terminal portions supported by said tube plates,

a plurality of parallel spacer plates supporting said tubes intermediate said terminal portions and dividing said shell into a plurality of bays extending transversely to said tubes,

said tubes and said spacer plates being arranged to provide an open centrally disposed core extending in an axial direction in said shell,

whereby incondensible gases and vapor to be condensed flow radially inwardly along said bays past said tubes and toward said core,

water box structure associated with said tube sheets and adapted to direct a cooling liquid in one direction through said tubes, said tubes thereby effecting cooling in said bays with a tube temperature gradient rising in said one direction,

said water box structure further being adapted to direct said cooling liquid in the opposite direction through said tubes, thereby reversing the tube temperature gradient in said bays and duct structure for conducting the collecting incondensible gases from said core, said duct structure having a plurality of first orifices for progressively venting the collecting incondensible gases from each bay at a rate increasing in said opposite direction when the cooling liquid is directed through said tubes in said one direction,

a plurality of second orifices for progressively venting the collecting incondensible gases from each bay at a rate increasing in said one direction when the cooling liquid is directed through said tubes in said opposite direction,

a partition disposed between said first and second orifices for restricting short circuiting flow of incondensible gases between said first and second orifices,

first and second incondensible gas ofltake conduits communicating with said first and second orifices, respectively, and

first and second valves disposed in said first and second olftake conduits, respectively, for selectively controlling flow of the incondensible gases from said first and second orifices.

References Cited by the Examiner UNITED STATES PATENTS 1,748,121 2/30 Gay 174 1,792,060 2/31 Bancel 1651l3 1,845,541 2/32 Smith 165l14 1,845,549 2/32 Meyer 165114 2,460,499 2/49 Grace 16595 CHARLES SUKALO, Primary Examiner. 

7. A SURFACE CONDENSER COMPRISING A TUBULAR SHELL HAVING A PAIR OF AXIALLY OPPOSED OPEN ENDS AND HAVING AN EXHAUST VAPOR INLET AND A CONDENSATE OUTLET, TUBE PLATES CLOSING THE AXIALLY OPPOSED ENDS OF SAID SHELL, A NEST OF TUBES EXTENDING FROM ONE END TO THE OTHER END OF SAID SHELL AND HAVING THEIR TERMINAL PORTIONS SUPPORTED BY SAID TUBE PLATES, SAID TUBES BEING ARRANGED TO PROVIDE AN OPEN CORE EXTENDING IN AN AXIAL DIRECTION IN SAID SHELL WITH THE TUBES ADJACENT SAID CORE CONSTITUTING A COOLING SECTION FOR INCONDENSIBLE GASES, FIRST WATER BOX STRUCTURE ASSOCIATED WITH ONE OF SAID TUBE PLATES AND ADAPTED TO DIRECT A COOLING LIQUID IN ONE DIRECTION THROUGH SAID TUBES, SAID TUBES THEREBY EFFECTING COOLING IN SAID COOLING SECTION WITH A VAPOR PRESSURE DROP GRADIENT DIMINISHING IN SAID ONE DIRECTION, SECOND WATER BOX STRUCTURE ASSOCIATED WITH ANOTHER OF SAID TUBE PLATES AND ADAPTED TO DIRECT SAID COOLING LIQUID IN THE OPPOSITE DIRECTION THROUGH SAID TUBES, WHEREBY SAID TUBES ATTAIN TUBE TEMPERATURE GRADIENT IN SAID OPPOSITE DIRECTION IN SAID COOLING SECTION, FIRST ORIFICE MEANS FOR PROGRESSIVELY VENTING THE COLLECTING INCONDENSIBLE GASES AT A RATE INCREASING IN SAID OPPOSITE DIRECTION WHEN THE COOLING LIQUID IS DIRECTED THROUGH SAID TUBES IN SAID ONE DIRECTION, SECOND ORIFICE MEANS FOR PROGRESSIVELY VENTING THE COLLECTING INCONDENSIBLE GASES AT A RATE INCREASING IN SAID ONE DIRECTION WHEN THE COOLING LIQUID IS DIRECTED THROUGH SAID TUBES IN SAID OPPOSITE DIRECTION, AND MEANS FOR RESTRICTING SHORT CIRCUITING FLOW OF INCONDENSIBLE GASES BETWEEN SAID FIRST AND SECOND ORIFICE MEANS. 